The nervous system is an integral part of the human body and its major function is to react to the external environment and to coordinate the function of the different parts of the body accordingly. The whole nervous system is divided into peripheral and central nervous systems. Although their physiological role is similar, there are significant differences in their functions. Nerves are responsible for transmitting electrical signals throughout the body to stimulate muscles and regulate the activity of vital organs. The central nervous system, which consists mainly of the brain and spinal cord, is responsible for creating electrical signals which are then sent throughout the body to initiate a response in an innervated organ or limb. The major function of the peripheral nervous system is to stimulate and initiate the contraction of the muscles which move different parts of the human body (mainly arms and legs), and regulate the activity of the internal organs. The nerves of the peripheral nervous system originate in the spinal cord and through long processes called axons innervate distant body parts. The message travels along the axon in the form of an electrical signal, called compound action potential (CAP). Thus, the peripheral nervous system consists of the different nerves through which the electrical signals travel throughout the body and electrical signals are transmitted from one nerve to another through axons, fiber-like extensions from a nerve cell.
An electrical signal traveling through a nerve is called an action potential. This potential is quantifiable and can be expressed in terms of voltage. This potential is responsible for initiating a response in an organ or limb. The strength of the compound action potential (the sum of the action potentials generate by several axons) correlates to the strength of the response. For example, if the compound action potential is sent through a peripheral nerve to initiate the contraction of a muscle, the stronger the compound action potential, the faster and/or stronger the muscle contraction will be.
Any impairment or inhibition in the transmission of the compound action potential can result in a weaker response from the innervated organ. Impairment of the compound action potential transmission could even result in paralysis of the skeletal muscles, i.e., the impairment causes the compound action potential to be too weak to initiate any response in the skeletal muscles, and thus, the patient is unable to move the limb, etc. There are various diseases and conditions in which the transmission of the compound action potential is impaired. Neuropathies such as distal axonopathies, myelinopathies, neuronopathies and autonomic neuropathies are all characterized by a significant reduction in the ability of the nerves to generate and transmit an action potential. Hyporeflexia and areflexia, characterized by weak or absent reflexes, are often linked to diminished compound action potential transmission. The symptoms of these diseases and conditions may be alleviated and the functioning of the innervated organs can be improved with a treatment that facilitates the transmission of the compound action potential.
As mentioned above, the role of the spinal cord, which is a part of the central nervous system, is to transmit the information between the brain and the peripheral nervous system. Any damage to the spinal cord may have devastating effects on the performance of the vital body function. The brain, besides controlling the activity of the spinal cord and peripheral nervous system, is responsible for learning and memory and for utilizing acquired information to improve survival skills.
Even a person without such a disease or condition could benefit from a treatment that facilitates compound action potential transmission. Such a treatment could enhance the performance of an innervated organ, enhancing the person's performance of an activity that utilizes the innervate organ. Furthermore, the treatment may be used to alleviate pain associated with a muscle, or to simply provide a person with a healthier feeling in that muscle.
Magnetic fields have been used in treatments for reducing pain, facilitation of bone healing and to promote overall muscle activity. The effect of a steady magnetic field on the compound action potential of sensory nerves have been described in McLean et al. “Effects of steady magnetic fields on action potentials of sensory neurons in vitro”, available at http://www.holcombhealthcare.com/reports/pub-effect.html, which is hereby incorporated by reference. The effects of a steady magnetic field on neuronal performance are not significant, and they are not sustained once the magnetic field is removed. Furthermore, there is some evidence that suggests that the body adapts to the steady magnetic field after a certain amount of time, and therefore exposure to that field will have no affect on neuronal performance.
Pulsed magnetic fields (PMF), i.e., magnetic fields in which the field strength is regularly alternated between different field strengths, have also been used in various treatments. Laycock, et al. “Pulsed magnetic field therapy and the physiotherapist”, available at http://www.tgselectronics.com.au/physio.html, which is hereby incorporated by reference, discusses using a PMF to resolve soft tissue injuries, facilitate bone fractures and reduce pain. Laycock describes that a “magnetic field pulsed at 5 Hz with a base frequency of 50 Hz” was as useful as an icepack in dispersing bruises and that a magnetic field having “a base frequency of 200 Hz pulsed at between 5 and 25 pulses per second” was most effective in reducing pain. The PMF used in such treatments is the result of using a magnetic field generating element with an AC power source. As the AC current alternates between its maximum positive and negative flows, the magnetic field pulsates between its maximum field strengths in both polarities, creating a saw-tooth like shaped magnetic field wave form, such as that shown in FIG. 1a. The magnetic field described in Laycock is one in which the saw-tooth like base magnetic field is alternately turned on and off at a given frequency, such as that shown in FIG. 1b. These treatments, however, do not produce significant improvements in neuronal performance.
It would therefore be desirable and advantageous to provide method and an apparatus of improving neuronal performance by facilitating the transmission of the compound action potential by exposure to a magnetic field that overcomes the disadvantages of the prior art, while at the same time improves neuronal performance.